System and method for cooling air

ABSTRACT

A system and method for cooling air includes using a refrigerant cooling system and further using a refrigerant liquefaction subsystem or method that includes using a heat sink cooler (“pre-cooler”) to cool the heat sink coolant before it is used to cool the refrigerant in the condenser. One aspect of the refrigerant liquefaction subsystem may use a water mist, which may be prepared by atomizers, high pressure nozzles, piezo-electric ultrasonic nebulizers, or the like, to cool the heat sink coolant.

RELATED PATENT APPLICATION

[0001] This application claims priority of U.S. Provisional ApplicationNo. 60/354,979, filed Feb. 8, 2002, entitled, “System and Method forCooling Air.”

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates to air conditioning systems andmore particularly to a system and method for cooling air that includesan air pre-cooler and may further include an additional cooler ofrefrigerant.

BACKGROUND OF THE INVENTION

[0003] Refrigeration systems or evaporative systems for cooling arewell-known in the art. Refrigeration is the process of removing heatfrom a substance or space in order to lower its temperature. To extractheat energy from the air, the air is placed in contact with a materialat a lower temperature so that heat flow will occur in a descendingtemperature gradient. The low-temperature material is usually either acold metal surface or a chilled-water spray. In either case, the workingsubstance of the system is an evaporating refrigerant in adirect-expansion cooling coil or in the tubes of a water chiller. Theenergy absorbed is rejected typically to the outdoors through anair-cooled condenser or cooling tower. The present invention ispresented in the context of cooling the airflow to an air-cooledcondenser, which is a common means of heat rejection.

[0004] The refrigerants, which are certain low-boiling-point substances,are used as the working fluid or heat-transfer media of typicalrefrigeration systems. They are used in a cyclical thermodynamic processthat involves two changes of state: between liquid and vapor and back.An example of a compression refrigeration cycle that uses adirect-expansion cooling coil is now presented.

[0005] Referring to FIG. 1, there is shown a basic compressionrefrigeration system 10 that has a closed refrigerant loop that is usedin a compression refrigeration cycle. In this cycle, there is analternate compression, liquefaction, expansion, and evaporation of therefrigerant. The air to be cooled is shown symbolically by arrow 12 atan initial temperature of T_(A1) and flows across an evaporator 14 thatremoves heat from the air to produce a cooled air represented by arrow16. The cooled air 16 is at a temperature T_(A2), where T_(A2)<T_(A1)

[0006] The evaporator 14 serves as the heat sink for removing the heatfrom the air 12. The refrigerant vaporizes there as it absorbs the heatthat is removed from air 12. The evaporator 14 may take one of severalforms. The evaporator 14 may be an extended surface (or finned) coolingcoil with a direct-expansion system or the heat exchanger coils of awater chiller for chilled water systems.

[0007] The heat in air 12 is delivered to the refrigerant in evaporator14 and the refrigerant, which is then at a pressure of P_(R2) and atemperature of T_(R2), is delivered to compressor 18. The compressor 18is a device for accomplishing primarily two functions. First, it removesvapor from the evaporator 14 at a rate that permits steady stateconditions of low temperature and low pressure in the evaporator 14.Second, the compressor 18 discharges the vapor at a pressure (P_(R3))and temperature (T_(R3)) high enough to permit heat rejection along adescending temperature gradient to the air or water of the condenser 20.

[0008] In the condenser 20, the heat originally removed from air 12 plusthe heat equivalent of the work performed in the compressor 18 arerejected to the condenser coolant (air or water) and ultimately to theoutside air or earth. The compression and removal of the heat from therefrigerant operate to return it to a liquid state at the condenserpressure, and the liquid refrigerant is collected by liquid receiver 22.From there, the refrigerant is delivered to an expansion valve 24. Theexpansion valve 24 produces a sudden drop in refrigerant pressure (i.e.,P_(R4)>>P_(R1)) and that in turn creates a sudden drop in temperature,T_(R4)>>T_(R1). And it regulates the flow of refrigerant producing auniform evaporating temperature for evaporator 14.

[0009] In a typical packaged air conditioning (rooftop unit) or splitair conditioning system, the compressor 18 and condenser 20 are locatedin a single unit outside the house or building. The compressor-condenserunit has a hermetically sealed compressor and motor in the middle offinned-tube air-cooled condenser forming the sides of a u-shaped (orsimilar) housing. The unit has a condenser fan and motor located on atop portion of the housing to provide a flow of outside, ambient airacross the condenser fins and out of an open top portion. The size ofsystems varies according to the cooling needs.

[0010] The cooling load on a space to be conditioned is substantiallylinear on a graph if the cooling load is placed on the ordinate and theoutside temperature on the abscissa. Typically an air conditioningunit's cooling capacity versus temperature is also nearly linear on thesame graph with high cooling capacity at lower outdoor temperatures andless cooling capacity at higher temperatures. For example, a Carrier48TJ006 (5 Ton) unit developing air at the evaporator at 67 F. will havea cooling capacity of 65.5 MBtu/hr. at 85 F., but only 56.5 at 105 F.,which is a drop of about 14% capacity as the outside temperature wentfrom 85 to 105 F. There is also about a 13% increase in powerconsumption at the higher outdoor temperature. Cumulatively, there is areduction in efficiency of about 24%. This type of information is usedto size air conditioning systems for a given space and conditions.

[0011] The American Society of Heating, Refrigeration andAir-Conditioning (ASHRAE) provides guidelines for helping to size a unitfor a given application. ASHRAE set the standards by which one sizesunless an ordinance requires otherwise. To size the air conditioningunit, the intersection of the linear (or nearly linear) capacity of theair conditioner with the linear loading profile of the space is locatedfor the maximum design temperature for the outside, ambient air. If asystem goes above the maximum temperature for which the unit was sized,the air conditioning unit will never catch up and cool the space down tothe desired temperature. To conservatively size the unit to handle thehottest days of the year, a substantial amount of the required capacityis needed just for the hottest days. For example, a 5-ton unit might beneeded to handle the hottest days, but in fact a 4-ton unit would dowell for the vast majority of the year. It would thus be nice to size aunit to handle the majority of the temperature range without beingunduly influenced by the end point—i.e., the hottest days.

[0012] Numerous efforts have previously been made to enhance the designof air conditioning systems and particularly air conditioning systemsthat reject heat through air cooled condensers. Some approaches haveinvolved adding supplemental refrigerant coolers and some that havetinkered with the condenser cooler itself For example, U.S. Pat. No.5,553,463 describes a system that includes a supplemental condenser forcooling the refrigerant with a closed-water loop that has a coolingtower. The refrigerant is cooled some by the closed-water system beforegoing to the condenser coil. Improvements remain desirable.

SUMMARY OF THE INVENTION

[0013] Therefore, a need has arisen for a system and method for coolingair that address shortcomings of previous systems and methods. Accordingto an aspect of the present invention, a method for cooling air with arefrigerant system is provided that includes the steps of passing air,which is at a temperature T_(A1) and is to be cooled, over an evaporatorthat contains a refrigerant that becomes vaporized and that removes heatfrom the air to produce conditioned air at a temperature T_(A2), whereT_(A2)<T_(A1); passing the refrigerant to a compressor where thevaporized refrigerant is compressed; passing the refrigerant to acondenser unit that removes heat from the refrigerant such that betweenthe refrigerant passing the compressor and condenser substantially allthe refrigerant is placed in a liquid state; passing the refrigerant toan expansion device that expands the refrigerant while passing it to theevaporator that allows for the refrigerant to be vaporized in theevaporator as the air at T_(A1) is cooled; passing a first heat-sinkcoolant at a temperature T_(HS1) over a heat-sink coolant cooler (whichmay also be referred to as “pre-cooler” and which may use atomized mistor other means) to lower the temperature of the heat-sink coolant to atemperature T_(HS2) and to thereby form a second heat-sink coolant; andpassing the second heat-sink coolant over the condenser to remove heatfrom the refrigerant in the condenser. In another embodiment, the methodincludes the steps of supplying air over two condenser coils andsupplying water directly on one of the coils to cool the coil but alsoto cool the air going over before it encounters the other coil. Inanother embodiment, the method includes cooling the refrigerant in partwith a heat exchanger and using the rejected heat to assist in heating awater supply reservoir. According to other aspects of the presentinvention, a controller may be used to control the operation of arefrigerant cooling system to regulate how much water is used comparedto how much electricity is used. In another embodiment, the controllermaybe designed for remote operation by, for example, the electric powercompany. This summary is not complete; please refer to the claims atend.

[0014] The present invention provides advantages; a number of examplesfollow. An advantage of the present invention is that it allows forlower (compared with similar units not incorporating the invention)electrical energy consumption during the hottest times of the year—thetimes when electrical companies experience peak demand. An advantage ofthe present invention is that air conditioning units can be sized fortemperatures closer to average summer temperature rather than peak ormaximum summer temperature. Another advantage is that the presentinvention will allow smaller, relatively less expensive units. Anotheradvantage is that the small units will run for longer duration, andtherefore, remove more water vapor from the air and thereby improvehumidity control. Yet another advantage of the present in invention, inone embodiment, is that an existing air conditioner with an air cooledcondenser can be retrofitted to use less electricity and to increase itscooling capacity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a more complete understanding of the present invention andadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings in which likereference numbers indicate like features, and wherein:

[0016]FIG. 1 is a prior art schematic diagram of arefrigeration-compression cooling system;

[0017]FIG. 2 is a schematic diagram of a cooling system according to oneembodiment of the present invention;

[0018]FIG. 3 is a schematic plan view of a refrigerant-liquefactionsubsystem according to an aspect of the present invention that is wellsuited for retrofitting existing air conditioning systems;

[0019]FIG. 4 is a schematic plan view of a refrigerant-liquefactionsubsystem for an air cooling system as might be implemented by anoriginal equipment manufacture; and

[0020]FIG. 5 is a schematic plan view of a refrigerant-liquefactionsubsystem for an air cooling system according to another aspect of thepresent invention;

[0021]FIG. 6 is a schematic plan view of a refrigerant-liquefactionsubsystem according to an aspect of the present invention; and

[0022]FIG. 7 is another schematic diagram of a refrigerant-liquefactionsubsystem according to an aspect of the present invention that is wellsuited to building that also require large amounts of hot water such asrestaurant kitchens and laundries.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The preferred embodiment of the present invention and itsadvantages are best understood by referring to FIGS. 2-7 of thedrawings, like numerals being used for like and corresponding parts ofthe various drawings.

[0024] Referring to FIG. 2, there is shown a system 110 for cooling aconditioned space or air represented by arrow 112. Air 112, which is ata temperature T_(A1), passes across an evaporator 114 that removes heatfrom air 112 to produce cooled or conditioned air represented by arrow116, which is at a temperature T_(A2). The heat removed in evaporator114 is delivered to a refrigerant within the evaporator 114. Therefrigerant is at a temperature T_(R1) and a pressure P_(R1) beforeentering the evaporator 114. The heat rejected from air 112 to therefrigerant in the evaporator 114 vaporizes the refrigerant and mayraise the temperature to T_(R2). The refrigerant is delivered fromevaporator 114 to compressor 118 by conduit 117.

[0025] The compressor 118 increases the pressure of the refrigerant fromP_(R2) to P_(R3) (i.e., P_(R2)<P_(R3)). The compressed refrigerant isthen delivered by conduit 119 to condenser 120. There the refrigerant iscooled to form a refrigerant that is in a liquid state. The liquidrefrigerant is delivered by conduit 121 to liquid receiver 122. Therefrigerant is then delivered by conduit 123 to an expansion device orvalve 124, which regulates the flow and lowers the pressure as necessaryfor delivery by conduit 125 to the evaporator 114 at temperature T_(R1),and thus forms the final portion of a closed refrigerant loop.

[0026] The aspect of system 110 that receives the vaporized, heatedrefrigerant and produces a liquid state refrigerant may be referred toas the refrigerant-liquefaction subsystem 126 or the “condensing unit.”The subsystem 126 includes compressor 118, condenser 120, liquidreceiver 122 (which can be integral with the condenser), and importantlyfurther includes a heat-sink coolant cooler or heat-sink air coolersubsystem 128. According to an aspect of the invention, subsystem 128may take numerous forms that may further include features to automate itto operate only when needed in extreme ambient heat.

[0027] In the embodiment shown, subsystem 128 includes a cooling unit128 that receives ambient, outside air or heat-sink air represented byarrow 130 at a temperature T_(HS1). It is referred to as heat-sink airsince it serves as the heat sink for the condenser 120. The subsystem128 cools the air 130 down to T_(HS2) to form a second heat-sink airrepresented by arrow 132. Heat-sink air 132 then flows across thecondenser 120 to remove heat from the refrigerant in the condenser andthen exits with a temperature T_(HS3) as shown by arrow 134. Anadvantage of this embodiment is that T_(HS2)<T_(HS1), which improves andincreases the heat rejectino of the condenser 120.

[0028] The heat-sink air cooler subsystem 128 further may include acontroller 136 that is coupled to a plurality of transducers representedby sensor or transducer 138 and may be further coupled to the compressormotor as suggested by connection 140. The controller 136, which containsa microprocessor, is operable to monitor the transducers 138, whichmeasure various characteristics of the initial outside air 130, such aswet-bulb temperature and dry-bulb temperature (or enthalpy), and tomonitor the load on the compressor through connection 140. Thecompressor load could be monitored by measuring motor current orrefrigerant discharge temperature, T_(R3). With this information, thecontroller 136 can determine the amount cooling needed by subsystem 128,if any.

[0029] To control the cooling of unit 128, the controller 136 can adjustthe liquid flow rate for cooler 128 when the cooler 128 is the preferredatomizer type described further below. A water supply line 135 provideswater to cooler 128. Water supply line 135 includes a water-treatingunit 137 (e.g., water softener, water filter, reverse osmosis filter,and/or other water treatment devices) and a control valve 139.Controller 136 has the ability to couple and adjust valve 139. Watertreatment device 137 may be added in places where the water needs to besoftened or filtered to minimize the possibility that the nozzles ordevices used in cooler 128 will become clogged by contaminants (lime,calcium, carbonates, etc.). Water treatment device 137 may also be anintense magnetic field, which may alter the mineral deposits fromcalcite to aragonite. The water demands for the system is not very high;for example, a five-ton unit would only need about several gallons anhour. One may wish to employ a water softener or filter when the waterhardness exceeds about 3 to 5 grains per gallon. As an additionalbenefit, the conditioned water may allow for water to be applieddirectly on to the surface of the condenser coils if desired withoutsubstantial problems from mineral deposits.

[0030] Controller 136 may further adjust baffles and by-pass doors ifthe supplemental cooling of subsystem 128 is not necessary or is notefficient under the current conditions. With respect to the latter, thecontroller 136 may be programmed to include the current price of waterused by cooler 128 and the price of electricity to help economicallyoptimize use of the overall system 110. Controller 136 may be tied (bytelephone line or wireless systems) into the electrical company whocould remotely indicate when it needs the system 110 to use subsystem128 to lower the electrical load on the system 110 (the electricalcompanies are motivated to give price breaks for this type of control).

[0031] In some embodiments, it may be desirable to forego a controllerand use a system that is either on or off or to use a system with simpletiming circuit. As an example of the latter, the timer may activate thecooler 128 only during the hottest hours of the day or possibly when thecompressor has operated continuously for more than 20 minutes.

[0032] The water used by cooler 128 is primarily evaporated to cool theair 130. Accordingly, very little water must be disposed of through adrain or otherwise. The atomizers of one embodiment of cooler 128 sprayonly enough water to evaporate—there is no need to re-circulate waterand no need for a cooling tower. Because there is no re-circulation, anycontaminants in the water do not build up. The subsystem 128 ispreferably designed to be used only during the hottest times of theyear, but has considerable influence on the efficiency since that is adesign point.

[0033] By reducing the temperature of air 130 from a temperature of, forexample, 105 F. to 85 F., the cooling capacity of a given airconditioning system 110 is increased while simultaneously decreasing theelectrical usage. As a specific example, a five-ton Carrier Unit (modelNo. 38CKS060) would experience an increased capacity of about 11.5%while the kilowatt usage decreases about 17.9%. These combine to improvethe energy efficiency ratio (BtuH of cooling per Watt of input power)from about 8.0 to 10.9—that is a 35.8% improvement. A fraction of thesavings is offset by water usage and/or increasing condenser fan power,but the remaining savings is still substantial.

[0034] Cooler 128 may take a number of different forms that use watermist or spray to cool the air (or other condenser coolant). Domesticwater may be used or water may be pumped to a high pressure and sprayedthrough stainless steel nozzles to produce sub-one-micron mist or spray.Alternatively, piezo-electric ultrasonic nebulizers or atomizers may beused. The nebulizers and atomizers produce more of a fog than a spray.The spray or mist increases the water surface area, which decreases thetime or travel length required for evaporation and eliminates thepossibility of standing water. It is probably good to avoid standingwater since it could develop a bacteria issue or a mosquito larvaehabitat.

[0035] As described in connection with FIG. 3, therefrigerant-liquefaction subsystem (e.g., 126 in FIG. 2) may be placedin a housing that further augments the performance by providing bafflingor intake nozzles of a spiral shape or other shapes that increase thevorticity of the air flow therein. The baffles can be made from manytypes of materials, such as of simple sheet metal or injection moldedplastic parts. The baffles may go in and be curved to impart a swirl orany other vortex generating design might be used. This increases thetotal velocity of the airflow, which increases the heat transfer rate byimproving the convection coefficient. It also increases the total travellength of the airflow, giving more distance for the fine water dropletsor mist to evaporate. This in turn further lowers the dry-bulbtemperature. In addition, motorized dampers can be added downstream ofthe mist nozzles for a dual purpose. They can be fully open when thecooler 228 is off in order to increase overall airflow and minimizepressure losses and condenser fan power required. They can also bemodulated to improve mixing and evaporation when the cooler 228 is on.In either case, the controller 236 may be connected to the dampers tocontrol them as desired.

[0036] Continuing to reference FIG. 3, a refrigerant-liquefactionsubsystem 226 is shown that may be used as part of a residential orother split-system air conditioning system, such as system 110 of FIG.2. In subsystem 226, the refrigerant is delivered by conduit 217 fromthe evaporator to compressor 218. Compressor 218 compresses therefrigerant and delivers it to the condenser 220. In particular, itdelivers the refrigerant to the condenser coils that surround acondenser fan 250. The cooled refrigerant is then delivered to conduit223 from where it is delivered to an expansion valve and on through theremaining portions of a closed-loop refrigerant system. The illustrativeembodiment of subsystem 226 is particularly well suited for retrofittingexisting residential air conditioning systems.

[0037] In retrofitting a typical split-system air conditioning system, acooling box 251 is formed by panels or baffling 252 around the coils 220as shown. The panels 252 may include insulation to minimize heattransfer with the first heat-sink air. The panels 252 form most of box251 that directs airflow from an opening on the first end 254 to anopening over the condenser fan 250. The opening on the first end 254 maycontain a heat-sink air cooling fan 256 that supplements fan 250 andpulls outside, ambient air 230 past a cooler or cooling unit 228. Therecan also be a second opening, second heat-sink fan, and second atomizerzone on the second end of the enclosure.

[0038] In this embodiment, cooling unit 228 is formed by a plurality ofatomizing nozzles 258 that form a water mist in what may be referred toas a mist zone downstream of the fan 256. The distance between the firstopening and the condenser is selected to allow substantially all of theatomized water to evaporate before it arrives at the condenser coils.Alternatively, with treated water, the atomized water may not allevaporate before the condenser coils and would actually moisten thecoils directly as well. To make a smaller (shorter) unit, internalbaffles may be used to make the internal flow path longer.

[0039] Atomizers are preferred that make a fine mist or droplets ofwater that are added to the air to evaporatively cool it to form acooled heat-sink air 232. With good evaporation the temperature willapproach the wet-bulb temperature. The cooled heat-sink air 232 thentravels across condenser 220, through fan 250, and out the top of thebox 251. The cooling unit 228 has a water supply line 262 and mayfurther include a pump 260. Line 262 preferably includes a waterconditioning or treatment unit 237 and a control valve 239. Aprogrammable controller 236 may be provided to control the operation ofsubsystem 226 or aspects of it.

[0040] The controller 236 may be coupled to a plurality of sensors ortransducers represented by transducer 238 to measure the conditions ofair 230. The controller 236 may also be coupled by a connection tocontrol valve 239 and by connection 265 to compressor 218. Thecontroller 236 uses a microprocessor and programming to receive inputsfrom the transducers and devices 238 and to adjust the flow of valve 239and also may control baffling such as 266 or bypass doors such as 268and 270. Doors 268 and 270 are shown in the closed position and inbroken lines in the open or by-pass position. The electrical connectionsof the moveable baffling and gates to the controller are symbolicallydepicted by connections 274 and 276 off of the controller. As with theprevious embodiment, the controller may also be tied into theelectrical/power company who could remotely control the extent to whichthe subsystem 226 operates.

[0041] Referring now to FIG. 4, there is shown arefrigerant-liquefaction subsystem 326 that may be more desirable foruse by an original equipment manufacturer (OEM). The subsystem 326 isanalogous in most respects to subsystem 226 of FIG. 3, except for thecondenser 320 can be readily placed in other positions as desired forease of manufacture. With a factory built model, the manufacturer may beable to use less condenser coils. Corresponding parts between FIG. 4 andFIG. 3 are shown with the same reference numerals except 100 has beenadded to each. The OEM may choose to increase the horsepower of fan 350and eliminate the need for supplemental fan 356 (which is optional).

[0042] Referring now to FIG. 5, another embodiment of arefrigerant-liquefaction subsystem 426 is presented. Subsystem 426 issimilar in most respects to subsystem 226 of FIG. 3, except that asupplemental condensing coil 480 replaces the mist nozzles 258. Coil 480may be of the same material and manufacture as coil 420 or it may beTEFLON (or similar coating) coated to improve its resistance to mineralbuild-up. Similar to FIG. 3, the water is supplied through conduit 462and may be filtered, treated, and/or softened by water treatment unit437. The water flow is controlled by valves 439 and controller 436. Inthis embodiment, the water is dripped from openings in conduit 428directly onto coil 480.

[0043] Coil 480 not only provides a surface for evaporating the water toprecool the airflow 432, but it also substantially increases the totalcondenser coil area further enhancing the refrigerant liquefactionprocess. The supplemental fan 456 may not be necessary if the free areafor airflow of coil 480 is comparable or greater than that of coil 420.

[0044] Two bypass valves 490 allow for the removal of coil 480 forcleaning (e.g., removal of any mineral deposits). In areas where thewater is particularly hard, e.g., greater than 10 grains per gallon orwhere the water is moderately hard and a water treatment unit 437 is notemployed, cleaning will be necessary. With coil 480 temporarily removed,the refrigerant flows through bypass conduit 492 and the remaining unit426 can still operate.

[0045] Referring to FIG. 6, another embodiment of therefrigerant-liquefaction subsystem 626 is presented. Subsystem 626 iswell suited for tight locations and where substantial performanceenhancement with minimal cost is desired. In this subsystem, a mist isproduced by multiple atomizer or mister nozzles 658 placed around thecondenser coils (like 220 in FIG. 3). Domestic water under normal cityor municipal pressure, enters subsystem 626 through conduit 662. A watertreatment device 637, which in this embodiment is shown as a coilproducing an intense magnetic field, may be placed on conduit 662. Thetreatment device 637 and an automated control valve 639 are selectivelyenergized by programmable controller 636. When valve 639 is open, waterpasses into conduit network 628 and is distributed to nozzles 658.Nozzles 658 supply a mist or droplets onto the condenser coils. Thisembodiment provides easy installation of the subsystem on an existingair conditioner and provides easy access to the nozzles 658.

[0046] Referring to FIG. 7, another embodiment of arefrigerant-liquefaction subsystem 526 is presented. Subsystem 526 isparticularly well suited for use in locations that require largequantities of hot water, e.g., restaurants, hotels, and laundries. Therefrigerant from the evaporator is delivered by conduit 517 tocompressor 518, where it is compressed. The heated refrigerant isdelivered by conduit 527 to heat exchanger 529 and then by conduit 531to condenser 520. Heat sink air cooler subsystem 528 receives ambientair 530, cools it, and delivers the air 532 to condenser 520 where it isdischarged 534. The condenser 520 cools the refrigerant and then it isdelivered by conduit 523 to the evaporator. The heat exchanger 529 mayalternatively be located on conduit 523 and receive refrigerant after ithas exited condenser 520.

[0047] An important aspect of this embodiment, is the heat exchanger 529and related aspects. The heated refrigerant in exchanger 529 rejectsheat to water delivered from a water supply tank 533 by conduit 541. Thewater that receives the heat in the exchanger 529 is delivered byconduit 543 back to tank 533. Tank 533 is used, at least when compressor518 is operating, as a water supply to water heater 545. The supplywater is delivered by conduit 547. Heated water is supplied to otherlocations from the heater 545 by conduit 561.

[0048] As hot water is used through conduit 561, it is made up from thecold water supply line 549. Water can be supplied to heater 545 or tank533. When the condenser 518 is operating, valve 553 may be closed andvalve 555 opened so tank 533 is used as the source of hot water to makeup water in heater 545. In that case, water is supplied from 549 to tank533. Pump 557 is used to pump water from tank 533 to the heat exchanger529 and back to tank 533. By using heat exchanger 529, the performanceefficiency of the subsystem 526 is improved with respect to rejection ofheat and by supplying heat to the water of tank 533, the performance ofthe water heating unit 559 is also improved. Note improved performancegained with respect to the heating unit 559 could be obtained even ifheat sink cooler subsystem 528 were excluded.

[0049] Although the present invention and its advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made therein without departing fromthe spirit and scope of invention as defined by the appended claims.Among other things, the possible changes include mixing and matchingfeatures of the various embodiments.

What is claimed is:
 1. A method for cooling air with a refrigerantsystem, the method comprising: passing air, which is at a temperatureT_(A1), that is to be cooled over an evaporator that contains arefrigerant that becomes vaporized and that removes heat from the air toproduce conditioned air at a temperature T_(A2), where T_(A2)<T_(A1);passing the refrigerant to a compressor where the vaporized refrigerantis compressed; passing the refrigerant to a condenser unit that removesheat from the refrigerant such that between the refrigerant passing thecompressor and condenser, substantially all the refrigerant is placed ina liquid state; passing the refrigerant to an expansion device thatexpands the refrigerant while passing it to the evaporator, which allowsfor the refrigerant to be vaporized in the evaporator as the air atT_(A1) is cooled; passing a first heat-sink coolant at a temperatureT_(HS1) over a heat-sink coolant cooler to lower the temperature of theheat-sink coolant to a temperature T_(HS2) to form a second heat-sinkcoolant; and passing the second heat-sink coolant over the condenser toremove heat from the refrigerant in the condenser.
 2. The method ofclaim 1, wherein the first heat-sink coolant comprises air and whereinthe step of passing a first-heat sink coolant over the heat-sink coolantcooler comprises the step of passing the first heat-sink coolant throughan atomized mist of water.
 3. The method of claim 2, further comprisingtreating a water supply to remove or neutralize contaminants andsupplying the treated water to an atomizer that produces the atomizedmist of water.
 4. The method of claim 1 further including the step ofplacing treated, atomized water directly on the condenser.
 5. The methodof claim 4, further comprising treating a water supply to removeminerals and supplying the treated water to an atomizer that producesthe atomized water to be sprayed on the condenser.
 6. The method ofclaim 1 further comprising the step of monitoring characteristics of thefirst heat-sink coolant with sensors coupled to a controller and usingthe controller to adjust the extent of cooling performed by theheat-sink coolant cooler.
 7. The method of claim 1, further comprisingthe step of controlling the water flow from a remote location.
 8. Themethod of claim 1, further including the step of activating theheat-sink coolant cooler with a timing circuit for only pre-set timeintervals.
 9. The method of claim 1, wherein the first heat-sink coolantcomprises air and wherein the step of passing a first-heat sink coolantover the heat-sink coolant cooler comprises the step of passing thefirst heat-sink coolant through a mist of water prepared with apiezo-electric ultrasonic nebulizer.
 10. The method of claim 1, whereinthe first heat-sink coolant comprises air and wherein the step ofpassing a first-heat sink coolant over the heat-sink coolant coolercomprises the step of passing the first heat-sink coolant through a mistof water prepared with nozzles.
 11. The method of claim 1, wherein thefirst heat-sink coolant comprises air and wherein the step of passingthe second heat-sink coolant over the condenser comprises passing thesecond heat-sink coolant over a first condenser coil followed by asecond condenser coil.
 12. The method of claim 11 further comprising thestep of spraying water to be evaporated on the first condenser coil. 13.The method of claim 11 further comprising the step of dripping water tobe evaporated on the first condenser coil.
 14. The method of claim 11further comprising the step of passing the refrigerant through a heatexchange to reject heat to water and then using the water as a supplysource for a water heater.
 15. An improved refrigerant cooling system ofthe type having: an evaporator for removing heat from the air to becooled such that the temperature is lowered from T_(A1) to T_(A2) andwhereby the removed heat is delivered to the refrigerant in theevaporator and whereby the refrigerant is vaporized, a compressorfluidly coupled to the evaporator to receive refrigerant therefrom andto increase the pressure of the refrigerant, a condenser fluidly coupledto the compressor for receiving refrigerant from the compressor andcooling the refrigerant, whereby the compressor and condenser areoperable to convert the refrigerant to a liquid state, and an expansionvalve fluidly coupled to the condenser for receiving liquid refrigerantfrom the condenser and for lowering the pressure of the refrigerant, theexpansion valve also being fluidly coupled to the evaporator fordelivering the refrigerant to the evaporator; wherein the improvementcomprises a heat-sink coolant cooler subsystem that uses sprayed waterto cool a heat-sink coolant before it passes over the condenser.
 16. Thesystem of claim 15 wherein the condenser has a fan and wherein theheat-sink-coolant cooler subsystem comprises: a device for producing awater mist; and a means for moving ambient air through the water mistand then across the condenser.
 17. The system of claim 16 wherein thedevice for producing a water mist comprises an atomizer.
 18. The systemof claim 16 wherein the device for producing a water mist comprises apressure water nozzle.
 19. The system of claim 16 wherein the device forproducing a water mist comprises a piezo-electric ultrasonic nebulizer.20. The system of claim 16 wherein the improvement further comprises: aplurality of sensors for measuring characteristics of the heat-sinkcoolant and the compressor load, a controller coupled to the pluralityof transducers and to the heat-sink coolant cooler subsystem, thecontroller operable to control the severity of cooling performed by theheat-sink cooler subsystem in response to inputs from the transducers.21. The system of claim 20 wherein the controller is operable to beremotely controlled.
 22. The system of claim 15 wherein the heat-sinkcoolant cooler subsystem comprises: a first condenser coil; a secondcondenser coil; and a means for preparing a water mist and deliveringdirectly onto the first condenser coil.
 23. A refrigerant cooling systemcomprising: an evaporator for removing heat from the air to be cooledsuch that the temperature is lowered from T_(A1) to T_(A2) and wherebythe removed heat is delivered to the refrigerant in the evaporator andwhereby the refrigerant is vaporized; a refrigerant liquefactionsubsystem comprising: a compressor fluidly coupled to the evaporator toreceive refrigerant therefrom and to increase the pressure of therefrigerant, a condenser fluidly coupled to the compressor for receivingrefrigerant from the compressor and cooling the refrigerant, whereby thecompressor and condenser are operable to move the refrigerant to aliquid state, and a heat sink air cooler unit for cooling air that isused as the heat sink for the condenser; an expansion valve fluidlycoupled to the condenser for receiving liquid refrigerant from thecondenser and for lowering the pressure of the refrigerant, theexpansion valve also being fluidly coupled to the evaporator fordelivering the refrigerant to the evaporator; wherein the refrigerantliquefaction subsystem further comprises: a condenser fan, an enclosureformed of panels and formed with a first opening on a first end and asecond opening proximate the condenser fan, a water supply line, acontrol valve coupled to the water supply line for selectivelycontrolling the water flow in the water supply line, a plurality ofwater atomizers coupled to the water supply line downstream of thecontrol valve, the atomizers operable to produce a water mist that isdelivered to a water mist zone; a controller having a microprocessor,the controller coupled to the control valve, a by-pass gate formed on aportion of the enclosure; a by-pass gate actuator coupled to the by-passgate for selectively opening closing the by-pass gate, and wherein theactuator is coupled to the controller, a plurality of sensors coupled tothe controller, the sensors operable to measure the wet-bulb temperatureand dry-bulb temperature of air located on an outside portion of theenclosure; and wherein the controller is programmed with prices ofelectricity and water and programmed to monitor inputs from the sensorsand to selectively control the control valve and by-pass gate to coolthe heat-sink air with the atomizers or to by-pass the atomizers tooptimize cost savings.
 24. The system of claim 23 wherein therefrigerant liquefaction subsystem further comprises: a heat-sink airfan disposed in the first opening of the enclosure, and a watertreatment unit for receiving water and removing any undesiredcontaminants and delivering treated water to a water supply line.
 25. Arefrigerant cooling system comprising: an evaporator for removing heatfrom the air to be cooled such that the temperature is lowered fromT_(A1) to T_(A2) and whereby the removed heat is delivered to therefrigerant in the evaporator and whereby the refrigerant is vaporized;a refrigerant liquefaction subsystem comprising: a compressor fluidlycoupled to the evaporator to receive refrigerant therefrom and toincrease the pressure of the refrigerant, a condenser, which has a firstcondenser coil and a second condenser coil, the condenser fluidlycoupled to the compressor for receiving refrigerant from the compressorand cooling the refrigerant, whereby the compressor and condenser areoperable to convert the refrigerant to a liquid state, and a watersupply line for supplying water directly onto the first condenser coil;an expansion valve fluidly coupled to the condenser for receiving liquidrefrigerant from the condenser and for lowering the pressure of therefrigerant, the expansion valve also being fluidly coupled to theevaporator for delivering the refrigerant to the evaporator.
 26. Arefrigerant cooling system comprising: an evaporator for removing heatfrom the air to be cooled such that the temperature is lowered fromT_(A1) to T_(A2) and whereby the removed heat is delivered to therefrigerant in the evaporator and whereby the refrigerant is vaporized;a refrigerant liquefaction subsystem comprising: a compressor fluidlycoupled to the evaporator to receive refrigerant therefrom and toincrease the pressure of the refrigerant, a condenser fluidly coupled tothe compressor for receiving refrigerant from the compressor and coolingthe refrigerant, whereby the compressor and condenser are operable toconvert the refrigerant to a liquid state, and; an expansion valvefluidly coupled to the condenser for receiving liquid refrigerant fromthe condenser and for lowering the pressure of the refrigerant, theexpansion valve also being fluidly coupled to the evaporator fordelivering the refrigerant to the evaporator; water reservoir tank; anda heat exchanger for rejecting heat from the refrigerant after thecompressor and before the condenser and wherein the heat is rejected towater from the water reservoir tank.
 27. A method of retrofitting anroof unit or split unit air conditioning unit having a condenser coil,the method comprising the steps of: placing a plurality of fluidlycoupled conduits proximate an exterior of the units condenser coils;coupling the conduits to a water supply source; and attaching aplurality of misting nozzles to the conduits.
 28. The method of claim 27further comprising the steps of providing a water treatment unit on thewater supply source to treat water before it is introduced to theplurality of nozzles.